1. Field of the Invention
The present invention refers to a tap for delivering liquids from vessels, in particular vessels of the rigid type or of the so-called “bag-in-box” type. The following description will refer to the application of the inventive tap onto a rigid vessel, commonly used for containing water or similar liquids, but it is obvious that the inventive tap, with a small number of adaptations and the creation of a profile adapted to be placed on an engagement mouth for this type of taps, can be used also on “bag-in-box” vessels or other types of vessels.
2. Background of the Invention
In order to deliver water from rigid vessels, very few arrangements of taps are known in the art, all composed by a very high number of parts, some of which, due to their nature, are also very costly: the final result is a highly costly tap, that cannot be made in practice, since it heavily affects the final cost of the liquid-vessel-tap product, cost that is given by the steps of molding and assembling and the plastic material used for producing the different pieces composing the tap.
Known taps are costly because, in applications with rigid vessels, to avoid having to drill the vessel itself so that air enters therein while liquid goes out, the tap had to be equipped with at least one passage for air that can be actuated (namely opened and closed) together with the liquid-delivering passage. However, all existing taps provide that the two above-mentioned passages are placed one above the other with respect to the liquid-delivering axis and are divided by at least one wall that allows “creating” a division between liquid outlet and air inlet: this compels to provide the tap with a control member to be made in two pieces, to obtain seal and operation. The external control piece (namely a sort of dome-shaped elastic pushbutton), to be made separately from the control piston, is a very costly piece of plastic elastic material, since it must guarantee the necessary elasticity and pulling force to keep the closing valve member against the (preferably cone-shaped) sealing wall: therefore, in prior art delivering taps, a front pushbutton is adopted, constrained to the valve opening/closing stem that performs, at the same time, a carrier function. Alternatively, some known taps, to allow the passage of liquid to deliver and air and to guarantee the actual division between air chamber and liquid chamber, must be internally equipped with suitable divisions made by means of various walls and geometries, and more pieces that complicate and increase the final tap price/cost.
In addition to this, there are taps with air passages created with many parts that are opened by rotation (and not through squashing of an elastic membrane), and that have a seal of the cylindrical type, but they have many problems: for example, they have no automatic closure, namely their closure must be performed by the user, they have no warranty seal and moreover they must also be internally equipped with suitable divisions made by means of various walls and geometries and many pieces that complicate and increase the final tap price/cost.
Moreover, in known taps, the protection cover is usually lacking a warranty seal and is kept onto the tap by constraint: the tampering-preventing warranty is provided by a costly heat-shrinking film that winds cover and tap and ensure the seal between cover itself and tap.
Moreover, in known taps, the dome-shaped elastic pushbutton making the external control is an autonomous piece connected to the external tap body and also has carrier functions, being also constrained to the internal stem in order to operate as spring, due to its own properties of reversible elastic deformation to “pull” the stem to bring it back to its closing position, usually against a rigid cone-shaped profile created on the tap body: usually, in fact, the body of known taps is very rigid while the stem must be produced with a soft material. Moreover, prior art taps can be adapted only on bottle necks suitably created with particular geometries.